Editing Gold (section)

=== Pollution ===
{{further|Mercury cycle|International Cyanide Management Code}}
Gold production is associated with contribution to hazardous [[Environmental effects of mining|pollution]].<ref>{{cite journal |last2=Marikar |first2=Fouzul |last1=Abdul-Wahab |title=The environmental impact of gold mines: pollution by heavy metals |journal=Central European Journal of Engineering  |volume=2 |issue=2 |pages=304–313 |date=24 October 2011 |bibcode=2012CEJE....2..304A|s2cid=3916088 |doi=10.2478/s13531-011-0052-3|doi-access=free }}</ref>

Low-grade gold ore may contain less than one [[Parts per million|ppm]] gold metal; such ore is [[Milling (grinding)|ground]] and mixed with [[sodium cyanide]] to dissolve the gold. Cyanide is a highly poisonous chemical, which can kill living creatures when exposed in minute quantities. Many [[List of gold mining disasters|cyanide spills]]<ref>[http://www.deseretnews.com/article/810435/Cyanide-spill-compared-to-Chernobyls---N-disaster.html Cyanide spills from gold mine compared to Chernobyl's nuclear disaster] {{webarchive |url=https://web.archive.org/web/20180714135300/https://www.deseretnews.com/article/810435/Cyanide-spill-compared-to-Chernobyls---N-disaster.html |date=14 July 2018}}. Deseretnews.com (14 February 2000). Retrieved on 4 May 2012.</ref> from gold mines have occurred in both developed and developing countries which killed aquatic life in long stretches of affected rivers. Environmentalists consider these events major environmental disasters.<ref>[http://news.bbc.co.uk/2/hi/europe/642880.stm Death of a river] {{Webarchive|url=https://web.archive.org/web/20090109134649/http://news.bbc.co.uk/2/hi/europe/642880.stm |date=9 January 2009 }}. BBC News (15 February 2000). Retrieved on 4 May 2012.</ref><ref>[http://www.abc.net.au/am/stories/s98890.htm Cyanide spill second only to Chernobyl] {{Webarchive|url=https://web.archive.org/web/20170525072149/http://www.abc.net.au/am/stories/s98890.htm |date=25 May 2017 }}. Abc.net.au. 11 February 2000. Retrieved on 4 May 2012.</ref> Up to thirty tons of used ore can be dumped as waste for producing one troy ounce of gold.<ref name="NYT-2005">[https://www.nytimes.com/2005/10/24/international/24GOLD.html Behind gold's glitter, torn lands and pointed questions] {{Webarchive|url=https://web.archive.org/web/20150408113857/http://www.nytimes.com/2005/10/24/international/24GOLD.html |date=8 April 2015 }}, ''The New York Times'', 24 October 2005</ref> Gold ore dumps are the source of many heavy elements such as cadmium, lead, zinc, copper, [[arsenic]], [[selenium]] and mercury. When sulfide-bearing minerals in these ore dumps are exposed to air and water, the sulfide transforms into [[sulfuric acid]] which in turn dissolves these heavy metals facilitating their passage into surface water and ground water. This process is called [[acid mine drainage]]. These gold ore dumps contain long-term, highly [[hazardous waste]].<ref name="NYT-2005" />

It was once common to use mercury to recover gold from ore, but today the use of mercury is largely limited to small-scale individual miners.<ref>{{cite web |url=http://www.worstpolluted.org/files/FileUpload/files/WWPP_2012.pdf |archive-url=https://web.archive.org/web/20150402130613/http://www.worstpolluted.org/files/FileUpload/files/WWPP_2012.pdf |archive-date=2 April 2015 |url-status=live |title=Pollution from Artisanal Gold Mining, Blacksmith Institute Report 2012 |access-date=22 September 2015}}</ref> Minute quantities of mercury compounds can reach water bodies, causing heavy metal contamination. Mercury can then enter into the human food chain in the form of [[methylmercury]]. [[Mercury poisoning]] in humans can cause severe brain damage.<ref>{{cite web|last=Wroblewski|first=William|date=12 January 2022|title='Babies here are born sick': are Bolivia's gold mines poisoning its indigenous people?|url=https://www.theguardian.com/global-development/2022/jan/12/babies-here-are-born-sick-are-bolivias-gold-mines-poisoning-its-indigenous-people|access-date=12 January 2022|website=The Guardian|language=en}}</ref>

Gold extraction is also a highly energy-intensive industry, extracting ore from deep mines and grinding the large quantity of ore for further chemical extraction requires nearly 25 [[Kilowatt-hour|kWh]] of electricity per gram of gold produced.<ref>{{cite journal |doi=10.1016/j.jclepro.2012.01.042 |title=Using life cycle assessment to evaluate some environmental impacts of gold |date=2012 |last1=Norgate |first1=Terry |last2=Haque |first2=Nawshad |journal=Journal of Cleaner Production |volume=29–30 |pages=53–63}}</ref>